Determine whether the integration occurs at a unique or at multiple sites for Mu MuLV in rat cells (NRK) and for RSV-Prague B in duck cells. Determine the order of the integrated genes. This will involve making restriction maps of both the unintegrated and the integrated viral genomes. Providing the integration site is unique, further specific aims are to isolate the integration site. Characterize the integration site with respect to the number of times it occurs in a genome (reiteration frequency) and the composition of the neighboring cellular sequences. Determine the sequence of the integration site. Determine whether herpes simplex virus integrates into the human B lymphocyte genome during infection and transformation.